"Be yourself" is one of the most common pieces of moral advice and one of the most underexamined. Existentialists were the first to take it seriously as a philosophical problem. Sartre, Heidegger, and Beauvoir all argued that most of what we do is *inauthentic* — we let "the they" (Heidegger's term for impersonal social pressure) decide what we want, what we believe, who we become.
Authenticity, on this view, isn't a fixed self you discover. It's a stance you take toward your own life: claiming the choices you make as YOURS, not blaming circumstance or social role, owning the freedom and the responsibility together. Bad faith — Sartre's term — is the move where you pretend you couldn't have done otherwise, or that your role required it. Authentic action faces the freedom squarely.
Critics push back hard. Charles Taylor and Bernard Williams asked: authentic to WHAT? There's no neutral self underneath the social roles, no preference-list waiting to be revealed. We're constituted by our communities, our languages, our histories. The advice to "be yourself" can become its own form of bad faith — pretending you can stand outside your situation and pick a true self. The honest version asks something harder: not who are you, but who do you keep choosing to become, and is the choosing yours?